The correct answer is C. 1924 at Paris.
Table tennis was first introduced as a demonstration sport at the 1908 Summer Olympics in London. It was then again introduced as a demonstration sport at the 1920 Summer Olympics in Antwerp. It was finally introduced as an official medal sport at the 1924 Summer Olympics in Paris.
Option A is incorrect because table tennis was not introduced in the Olympics in 1896. It was first introduced as a demonstration sport in 1908.
Option B is incorrect because table tennis was not introduced in the Olympics in 1988. It was first introduced as an official medal sport in 1924.
Option D is incorrect because table tennis was not introduced in the Olympics in 1924 at Seoul. It was introduced in Paris.